Ovarian hyperstimulation syndrome — structured oral station (12 minutes)

Opening prompt — "Tell me what you do from the bedside."

Model response — say it in this order: ^[1][3]

• "This is severe ovarian hyperstimulation syndrome. She has clinical ascites, respiratory compromise, oliguria and a haematocrit of 0.50 — she is haemoconcentrating and her intravascular volume is depleted. I would alert my consultant and the reproductive medicine team, and move her to a high-dependency setting."
• "I would take strict daily weights, fluid balance and abdominal girth, repeat the haematocrit and renal function, and arrange a transvaginal ultrasound to quantify the ascites and exclude torsion. I would check a pregnancy test — this is likely late OHSS, which tracks pregnancy and is more severe."
• "My immediate management is careful volume and oncotic support, thromboprophylaxis, and paracentesis for her tense ascites — while never using hCG for luteal support."^[3]

Examiner is listening for: recognition that the normal blood pressure hides intravascular depletion, the severity grade, and parallel action (assess, investigate, treat). ^[1]

Probe 1 — "Her blood pressure is 100/64. How worried are you?"

• "Very — the danger in OHSS is not the blood pressure, it is the haematocrit. A normal-looking pressure hides a depleted intravascular volume because the missing fluid is in her peritoneum. Her haematocrit of 0.50 and her oliguria tell me she is haemoconcentrating and her renal perfusion is falling."^[3]
• "I would not be reassured by that pressure, and I would manage her volume status on the haematocrit, urine output and weight trend."^[3]

Probe 2 — "Explain the pathophysiology to me as if I were your fellow."

• "OHSS is a VEGF-driven hyperpermeability state. McClure showed that the major capillary permeability agent in OHSS ascites is vascular endothelial growth factor, and Abramov showed VEGF levels track the severe clinical picture."^[2]
• "The stimulated ovary releases VEGF, the capillaries leak protein-rich fluid into the third space — that is her ascites and her breathlessness — and the intravascular space empties, which is her haemoconcentration, oliguria and hypoalbuminaemia."^[2][3]
• "hCG is the amplifier: her trigger hCG and now endogenous pregnancy hCG drive VEGF release, which is why late OHSS is more severe and prolonged."^[6]

Probe 3 — "How will you manage her fluids, and would you drain her ascites?"

• "Fluids have to be balanced: crystalloid to restore intravascular volume, but titrated to urine output and haematocrit, balanced with colloid or albumin for her oncotic pressure — I must not drown the third space and worsen the ascites."^[3]
• "Yes, I would drain the tense ascites. SOGC recommends considering outpatient culdocentesis to prevent disease progression in severe OHSS, and Rizk recommends aspiration of ascitic fluid, preferably by the transvaginal route, in severe ascites. Relieving the pressure improves her renal perfusion, venous return and breathing."^[5][3]
• "And I would start prophylactic low-molecular-weight heparin and thromboembolic-deterrent stockings — thromboembolism, including arterial events, is the killer complication of severe OHSS."^[3]

Probe 4 — "She is frightened and asks if this will happen again. She is desperate for a baby."

This is a scored domain, not a courtesy. Demonstrate it out loud: ^[1]

• Move to her eye level, use her name, acknowledge the fear: "You are safe here — you have a serious but treatable reaction to the stimulation, and we are looking after the fluid and the clotting risk. I will explain each step."
• On recurrence: be honest but reassuring — "There is a real risk it could happen again with the same approach, so we will plan your next cycle differently — a gentler stimulation, a different trigger, and freezing embryos first — to make this far less likely."^[4][5]
• Acknowledge the emotional weight of infertility and OHSS together; offer a formal debrief and a named contact.

Probe 5 — "Design the prevention plan for her next cycle."

• "Individualise a low gonadotrophin dose; use a GnRH antagonist protocol with a GnRH agonist trigger instead of hCG — the single biggest lever against early OHSS."^[5]
• "Add metformin for her PCOS — it may reduce OHSS — and give cabergoline from the day of the trigger: the Cochrane review shows dopamine agonists reduce moderate-severe OHSS, OR 0.32."^[4][5]
• "Electively transfer a single embryo, or freeze all embryos and transfer later, to remove the pregnancy amplifier of late OHSS — and use progesterone, never hCG, for luteal support."^[5]